Like other electronic media connected to government officials, such as e-mail and Blackberry text messages, Twitter interactions are archived and thus subject to Congressional subpoena if warranted.
CBS News Radio White House correspondent Peter Maer asked Gibbs if the tweets of those who follow him on Twitter would be subject to the government archiving rules. Gibbs said he didn't know and would ask the lawyers.
It's unlikely that someone merely following the press secretary on Twitter would bring their tweets under government notice, but direct messages and "@" responses would likely be part of the archived record.
Twitter is becoming a powerful tool, with an extensive reach among the digitally literate, for debating issues 140 characters at a time. And, as a propaganda machine, it's clearly a lot more effective and cheaper than dropping leaflets from a plane.
Last month, President Obama himself sent out his first tweet while he was visiting the Red Cross Disaster Operations Center in Washington.
The White House also manages a White House Twitter account, with more than 1.7 million followers (Gibbs has less than 25,000 so far), and Organizing for America, the grassroots organization pushing the Obama agenda, has more than 3.3 million followers for its Barack Obama account.
Daniel Farber is editor-in-chief of CBSNews.com. You can read more of his posts in Hotsheet here. You can also follow him on Twitter.